ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Asset Retirement Obligation Disclosure) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2016 |
Dec. 31, 2015 |
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| Asset Retirement Obligation [Roll Forward] | Ìý | Ìý |
| Asset retirement obligation at beginning of period | $ 206.3 | $ 142.4 |
| Accretion expense | 2.5 | 6.5 |
| Exchange rate changes | 0.9 | (1.1) |
| Revision in estimated cash flows | (20.8) | 58.5 |
| Asset retirement obligation at end of period | $ 188.9 | $ 206.3 |
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- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of the Increase or Decrease in the amount of asset retirement obligations for the period associated with foreign currency translation (to the extent that the entity accounts for the foreign currency effects as a separate component of the change in the liability). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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